Major depression is one of the most prevalent mental disorders to afflict adults. It seriously impacts role functioning and typically takes a recurrent course. Although antidepressant medications have proven efficacy and are the most common treatment for depression, up to 70% of adults do not complete the recommended regimen. There is also evidence that cognitive-behavioral therapy in conjunction with medications is more effective than medications alone in preventing depression relapse. This project will develop and test an interactive multimedia intervention aimed at improving regimen adherence and preventing depression relapse for outpatients receiving antidepressants. Empirically validated frameworks will be adapted for self-administration via the Internet or CD-ROM. The intervention will consist of knowledge- and skills-based modules including: understanding depression, regimen adherence, mood monitoring, behavioral activation, cognitive restructuring, interpersonal relations, relaxation, and planning for the future. The competency-based instructional design will be structured for multiple sessions using video-based tutorials, testimonials, and behavior modeling vignettes. The Phase I prototype, targeted to women, with modules on understanding depression, regimen adherence, mood monitoring, and behavioral activation will be evaluated in a randomized trial. In Phase II, all eight modules will be developed, targeted to six gender and age groups, and evaluated in a randomized trial.